DC-DC Convertor Failure

Those are two different things, both contained in the inverter assembly.

Reference in the manuals to the "DC/DC converter" always means the simple buck converter from traction battery voltage down to aux battery voltage. That's located down below the main IPM in the inverter assembly.

When the manuals refer to the "boost converter", that's the big one that's in fact bidirectional: it boosts traction battery voltage up to 650 for operating the motors, and also bucks motor voltage down to traction battery voltage for regen and charging. The transistors for that one are part of the main IPM, though the reactor and capacitors needed in that circuit are separate parts.

 

Why is that?